AQA Jan 2013 Paper 2 Q1

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section a answer all questions in the spaces provided do not write outside the box a figure shows the volume of hydrogen gas collected when a sample of magnesium reacted with an excess of dilute hydrochloric acid the rate of this reaction can be studied by measuring the time it takes for a given volume of hydrogen to be collected figure volume of hydrogen cm a i state the meaning of the term rate of reaction time s mark a ii state and explain what has happened to the rate of this reaction at point w in figure marks wmp jan chem do not write outside the box a iii in terms of collision theory explain why at a fixed temperature the rate of this reaction doubles when the concentration of the hydrochloric acid doubles marks b in a study of the reaction in part a a student referred to activation energy b i state the meaning of the term activation energy mark b ii complete figure by drawing the shape of the reaction profile from reactants to products for an exothermic reaction show the position of the products show and label the activation energy figure energy reactants question continues on the next page marks turn over wmp jan chem do not write outside the box c barium metal reacts very quickly with dilute hydrochloric acid but it reacts more slowly with water c i write an equation for the reaction of barium with water mark c ii a solution containing barium ions can be used to show the presence of sulfate ions in an aqueous solution of sodium sulfate write the simplest ionic equation for the reaction that occurs and state what is observed simplest ionic equation observation marks c iii state one use of barium sulfate in medicine explain why this use is possible given that solutions containing barium ions are poisonous use explanation marks wmp jan chem turn over for the next question do not write on this page answer in the spaces provided turn over wmp jan chem

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